Thread pulling

After the glue has thoroughly dried, separate the three strips from the foil and cut off the ends of any loose threads. Pull on the... 

If / is the number of engaged threads, the axial load from this thread pull force creates a bending stress 5 and a shear stress S at the root of the shaft thread ... 

Figure 26 Two thread-pulling methods of measuring extensional viscosity.

Various other soft materials without the layer—lattice stmcture are used as soHd lubricants (58), eg, basic white lead or lead carbonate [598-63-0] used in thread compounds, lime [1305-78-8] as a carrier in wire drawing, talc [14807-96-6] and bentonite [1302-78-9] as fillers for grease for cable pulling, and zinc oxide [1314-13-2] in high load capacity greases. Graphite fluoride is effective as a thin-film lubricant up to 400°C and is especially useful with a suitable binder such as polyimide varnish (59). Boric acid has been shown to have promise as a self-replenishing soHd composite (60). 

These are required to make threads, i.e. the final drawing, twisting and winding of cotton. Such motors must possess very smooth acceleration to eliminate breakage of threads. They are recommended to have a starting torque of 150-200% of T, and a pull-out torque of 200-275% of with a mean acceleration torque ol 150-175%. A normal acceleration time of 5-10 seconds is recommended. Faster acceleration may cause more breakages, while a slower acceleration may result in snarls and knots in the yarn as a result of insufficient tension. 

Place clean protectors on the field end of the pipe so that the thread will not be damaged while rolling the pipe onto the rack and pulling it into the derrick. 

Caution the patient not to pull the threads. If partial expulsion occurs, removal is indicated and a new system inserted. 

Teach the patient to check after each menstrual period to make certain that the thread still protrudes from the cervix and caution her not to pull the thread. 

These are just a few examples of what could go wrong with an NOE experiment. NOE experiments are not boring and all the same as a chemist acquaintance once famously remarked. Quite the contrary in fact. Designing sensible experiments to make use of the NOE and dovetailing the results with other NMR data, can be quite challenging - and rewarding when you finally pull all the threads together to produce a sensible picture of a problem molecule. 

The capture threads also comprise similar components but here the microcrystals compose less than 5% of the thread, with both the amorphous and microcrystalline portions arranged in a more random fashion within the thread. Hydrated glue, which coats the thread, acts as a plasticizer imparting greater mobility and flexibility to the chains. It stretches several times its length when pulled and is able to withstand numerous shocks and pulls appropriate to contain the prey as it attempts to escape. Further, most threads are spun as two lines so that the resulting thread has a kind of built-in redundancy. 

The simplest method of melt-spinning is to melt the polymer in a test tube, dip a glass rod in the melt and pull it out slowly. The threads obtained in this manner are short and irregular so that they are not well suited for subsequent investigations. 

A solution of 3 ml (14 mmol) of freshly distilled sebacoyl dichloride (for preparation see above) in 100 ml of carbon tetrachloride is placed in a 250 ml beaker. A solution of 4.4 g (38 mmol) of hexamethylenediamine in 50 ml of water is carefully run on to the top of this solution, using a pipette. (The aqueous solution can be made more readily visible by coloring it with a few drops of phenolphthalein solution.) A polyamide film is immediately formed at the interface and can be pulled out from the center with tweezers or clamps and laid over some glass rods it can now be pulled out continuously in the form of a hollow thread and wound up on to a spool driven by a slow-running motor. The polycondensation comes rapidly to a standstill if the motor is stopped, but immediately recommences, even after some hours, when the motor is restarted. 

The drawn-off polyamide thread is thoroughly washed in 50% ethanol or in acetone, then with water and dried in vacuum at 30 °C.The Nylon-6,10 so obtained has the same physicai properties as that obtained by condensation in solution (see under above) or by melt condensation. It melts at 228 °C and can be spun from the melt by pulling with a glass rod the threads can be cold drawn. 

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